The present invention broadly relates to a hermetical motor-compressor of a relatively small capacity, having a compression mechanism confined within a closed container, suitable for use as the compressor of an electric refrigerator. More specifically, the present invention is concerned with an improved construction for feeding lubricating oil having a specific form of oil conduits or grooves of a rotor shaft of the compressor of the type stated above, especially when the rotor shaft is made basically by a plastic working of a single steel pipe, as well as an effective bearing structure making use of the rotor shaft.
Conventionally, it has been proposed to produce the rotor shafts of hermetical compressors efficiently by plastic working of single steel pipes. However, unfortunately, these rotor shafts have had various drawbacks or shortcomings, especially concerning the difficulty in forming the oil grooves or conduits therein, as will be detailed later.